1. Field of the Invention
The present invention relates generally to robotic arms and more particularly, to a robotic arm with a spherical linkage.
2. Description of the Related Art
A conventional robotic arm with a spherical five-bar linkage, such as that disclosed in unpublished Taiwan Patent Application No. 102121198, comprises four bent links connected two by two. Each of the bent links is defined with two axes of rotation at two ends thereof, and the axes of rotation all pass through a center of spherical rotation. The robotic arm is primarily applied in a minimally invasive surgery system for installation of a miniature surgical tool and accurate control of swinging direction and angel of the miniature surgical tool.
However, the aforesaid robotic arm is quite large because of having at least four bent links, and the minimally invasive surgery system usually comprises a plurality of robotic arms for installation of a plurality of miniature surgical tools having different functions. Therefore, it would be better to minimize the size of each robotic arm for the convenience of arranging the minimally invasive surgery system in quite limited room for surgery and the minimization of obstructing the motions of medical personnel.
Besides, the movements of the bent links of the aforesaid robotic arm are affected by each other, and drives for driving the bent links to rotate occupy some space around the bent links so as to restrict the rotating angel of each bent link. Therefore, the robotic arm can only drive the miniature surgical tool to move in a quite limited sphere of action.